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How can I convert NSDictionary to NSData and vice versa?
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363
NSDictionary -> NSData:
NSData *myData = [NSKeyedArchiver archivedDataWithRootObject:myDi...
MySQL foreign key constraints, cascade delete
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How to select rows from a DataFrame based on column values?
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4135
To select rows whose column value equals a scalar, some_value, use ==:
df.loc[df['column_name'...
Split column at delimiter in data frame [duplicate]
...me.
I added a "x|y" line to avoid ambiguities:
df <- data.frame(ID=11:13, FOO=c('a|b','b|c','x|y'))
foo <- data.frame(do.call('rbind', strsplit(as.character(df$FOO),'|',fixed=TRUE)))
Or, if you want to replace the columns in the existing data.frame:
within(df, FOO<-data.frame(do.call('r...
“Inner exception” (with traceback) in Python?
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Python 2
It's simple; pass the traceback as the third argument to raise.
import sys
class MyE...
What do ellipsis […] mean in a list?
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113
It means that you created an infinite list nested inside itself, which can not be printed. p co...
How to count the number of true elements in a NumPy bool array
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Create Git branch with current changes
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730
If you hadn't made any commit yet, only (1: branch) and (3: checkout) would be enough.
Or, in o...
Why does multiprocessing use only a single core after I import numpy?
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how to check redis instance version?
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$ redis-server --version
gives you the version.
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